Hydraulic steering device

Abstract

A hydraulic steering device ( 1 ) of a mobile machine, in particular of an industrial truck, includes a steering angle transmitter ( 2 ) in mechanically functional communication with a steering valve ( 4 ). As a function of the actuation of the steering angle transmitter ( 2 ), the steering valve ( 4 ) controls the connection of a steering drive ( 13 ) with a pressure fluid source ( 6 ) and a reservoir ( 11 ). To vary the translation ratio of the steering device in a simple manner, a bypass device ( 20 ) is operationally associated with the steering drive ( 13 ). By activation of the bypass device, the quantity of pressure fluid delivered from the pressure fluid source ( 6 ) to the steering drive ( 13 ) can be diverted to a reservoir ( 11 ).

1. A hydraulic steering device of a mobile machine, comprising:
 a steering angle transmitter functionally connected with a steering valve, wherein the steering valve controls a connection of a steering drive with a pressure fluid source and a reservoir as a function of activation of the steering angle transmitter; and 
 a bypass device functionally connected with the steering drive, wherein a quantity of pressure fluid delivered from the pressure fluid source to the steering drive can be diverted to said reservoir by the bypass device, 
 wherein, for actuation, the bypass device is functionally connected with an electronic control device. 
 
     
     
       2. The hydraulic steering device as recited in  claim 1 , wherein the bypass device comprises a control valve that performs a throttling action in intermediate positions and has a closed position and an open position, and wherein the control valve is actuated at a maximum translation ratio of a steering device into the closed position by a valve closing actuator and can be actuated toward the open position by a valve opening actuator to reduce the translation ratio of the steering device. 
     
     
       3. The hydraulic steering device as recited in  claim 2 , including a stop valve functionally connected to the control valve that opens toward the reservoir in the open position of the control valve. 
     
     
       4. The hydraulic steering device as recited in  claim 1 , wherein the bypass device is connected on an input side with an output of a shuttle valve device, and wherein the shuttle valve device is connected on an input side with a first pressure fluid line that leads from the steering valve to the steering drive and a second pressure fluid line that leads from the steering valve to the steering drive. 
     
     
       5. The hydraulic steering device as recited in  claim 1 , wherein the bypass device is electronically actuated by the electronic control device. 
     
     
       6. The hydraulic steering device as recited in  claim 2 , wherein wherein the valve opening actuator is an electromagnet. 
     
     
       7. The hydraulic steering device as recited in  claim 2 , wherein wherein the valve closing actuator is a spring. 
     
     
       8. The hydraulic steering device as recited in  claim 1 , wherein the electronic control device is functionally connected on an input side with at least one sensor device that measures a vehicle status. 
     
     
       9. The hydraulic steering device as recited in  claim 8 , wherein the sensor device is selected from the group consisting of a sensor device that detects a speed of travel of the mobile machine and a sensor device that detects cornering of the mobile machine. 
     
     
       10. The hydraulic steering device as recited in  claim 9 , wherein the sensor device is a steering angle sensor that is associated with the steering drive. 
     
     
       11. A hydraulic steering device of a mobile machine, comprising:
 a steering angle transmitter functionally connected with a steering valve, wherein the steering valve controls a connection of a steering drive with a pressure fluid source and a reservoir as a function of activation of the steering angle transmitter; and 
 a bypass device functionally connected with the steering drive, wherein a quantity of pressure fluid delivered from the pressure fluid source to the steering drive can be diverted to said reservoir by the bypass device, 
 wherein the bypass device comprises a control valve that performs a throttling action in intermediate positions and has a closed position and an open position, and wherein the control valve is actuated at a maximum translation ratio of a steering device into the closed position by a valve closing actuator and can be actuated toward the open position by a valve opening actuator to reduce the translation ratio of the steering device, and 
 wherein the bypass device is connected on an input side with an output of a shuttle valve device, and wherein the shuttle valve device is connected on an input side with a first pressure fluid line that leads from the steering valve to the steering drive and a second pressure fluid line that leads from the steering valve to the steering drive. 
 
     
     
       12. The hydraulic steering device as recited in  claim 2 , wherein the bypass device is electronically actuated by the electronic control device.